1. Field of the Invention
The present invention generally relates to a receptacle of an optical connector and more particularly, to a receptacle to be coupled with an optical plug and having a light receiving element module and a luminescence element module in a connector housing thereof.
2. Description of the Related Art
Referring to FIG. 14, a reference character 101 indicates an optical connector which is applied to a multiplex transmission circuit on, for example, a body of a motor vehicle, which optical connector 101 consists of a receptacle 102 and an optical plug 103.
As shown in FIGS. 14 and 15, the receptacle 102 has a connector housing 104 which has front and rear openings. Through the front opening of the connector housing 104 the optical plug 103 is coupled therewith (FIG. 14). And, as shown in FIG. 15, through the rear opening of the connector housing 104, a sleeve member 105, a light receiving element module 106 (an optical element module), a luminescence element module 107 (an optical element module), and a cap member 108 in a rectangular plate-like shape are fitted in turn.
Inside the connector housing 104, a coupling portion 109 to couple with the optical plug 103 (FIG. 14) through the front opening, accommodating chambers 110 to accommodate the light receiving element module 106 and the luminescence element module 107 from the rear opening, and transferring tube portions 111 connecting the coupling portion 109 (FIG. 14) and the accommodating chambers 110 are formed. An optical plug locking portion 113 formed on a top wall 112 of the connector housing 104 engages a locking arm 141 (FIGS. 14 and 16) of the optical plug 103 (FIG. 14). The locking arm 141 will be described later.
The accommodating chambers 110 are surrounded by a top wall 112, a bottom wall 114, right and left walls 115,116, and a partition wall 117, which partition wall 117 stands in the middle of the right and left walls 115,116 and forms the accommodating chamber 110 for the light receiving element module 106 and the chamber 110 the luminescence element module 107.
Engaging portions 119 to engage securing projections 118 (only two are shown) which are formed on top and bottom edge portions of the cap member 108 are formed on the top wall 112 over the accommodating chambers 110. And, terminal led-out portions 120 open on the bottom wall 114 under the accommodating chambers 110.
Terminals 121, 122 of the light receiving element module 106 and the luminescence element module 107, respectively, are put through wide portions of the respective terminal led-out portions 120. And, a pair of securing projections 118 formed on the top edge portion of the cap member 108 engage narrow portions of the respective engaging portions 119.
The pair of securing projections 118, which are on each of the top and bottom edge portions of the cap member 108, engage the engaging portions 119 and the terminal led-out portions 120, respectively, thereby to prevent the cap member 108 from falling off the rear opening.
As shown in FIG. 17, the transferring tube portion 111 is formed with a step. And, a small-diameter portion 135 (FIG. 16) of a ferrule member 133 (described later) is inserted in a front small-diameter portion 123 of the transferring tube portion 111, and the sleeve member 105 (FIG. 15) is inserted in a rear large-diameter portion 124 of the transferring tube portion 111.
On the other hand, as shown in FIG. 15, the sleeve member 105 is formed cylindrically and consists of an optical waveguide portion 125 made of glass or synthetic resin and a holder portion 126. The light receiving element module 106 and the luminescence element module 107 are formed by putting a light receiving element (not shown) and a luminescence element (not shown) in respective molded portions 127,128.
In the assembly of the receptacle 102, the light receiving element and the corresponding sleeve member 105 and also the luminescence element and the corresponding sleeve member 105 are aligned on the respective longitudinal axes of the respective transferring tube portions 111.
The above optical plug 103 includes, as shown in FIG. 16, a pair of ferrule member assemblies 129, a plug housing 130 (FIGS. 14 and 16) to accommodate the ferrule assemblies 129, and a spring cap 131 (FIGS. 14 and 16) to engage a rear portion of the plug housing 130 and to hold the ferrule assemblies 129.
The ferrule assembly 129 consists of an optical fiber cable 132, a ferrule member 133 attached to the end of the optical fiber cable 132, and a spring 134.
The ferrule member 133 is formed stepwise, a core portion (not shown) of the optical fiber cable 132 is inserted in a smaller-diameter portion 135 of the ferrule member 133, and a primary sheathing (not shown) of the optical fiber cable 132 is inserted in a large-diameter portion 137 of the ferrule member 133, which large-diameter portion 137 is provided with flanges 136. A reference character 138 indicates a secondary sheathing of the optical fiber cable 132.
The spring 134 is arranged between the rear side flange 136 and the spring cap 131 and pushes the ferrule member 133 forward.
The plug housing 130 is formed substantially as a box and has accommodating chambers 139 to accommodate the ferrule assemblies 129. And, the plug housing 130 is provided with a locking arm 141 on a top wall 140 thereof. The optical plug 103 is uncoupled from the receptacle 102 by pushing an end portion of the locking arm 141 (FIG. 14).
And, the plug housing 130 is, as shown in FIG. 14, provided with slit covers 142 at the rear ends of both side walls, which slit covers 142 project rearward from the respective rear ends.
The spring cap 131 is formed substantially as a cup and is provided with plug guiding slits 143 on respective side walls. The plug guiding slits 143 are closed with the respective slit covers 142 of the plug housing 130.
Against a rear inside plane of the spring cap 131 the springs 134 (FIG. 16) abut, and inside and in the middle of the spring cap 131 an engaging projection (not shown) to engage the plug housing 130 is formed.
The optical plug 103 is assembled by engaging the spring cap 131 with the plug housing 130 after fitting the ferrule assemblies 129 (only one being shown in FIG. 16) to the optical plug 103 through the plug guiding slits 143 of the spring cap 131. The ferrule assemblies 129 are accommodated in the accommodating chambers 139 (FIG. 16) and are locked by engaging projections 144 (only one being shown in FIG. 16) of the plug housing 130, which engaging projection 144 is positioned between the pair of flanges 136 of the ferrule members 133.
As described above, the ferrule assemblies 129 are pushed forward by the springs 134 (one being shown) and the forward movement of the ferrule assemblies 129 is limited by the stoppers 145 formed in the accommodating chambers 139.
In the above structure, on coupling of the optical plug 103 with the receptacle 102 the transferring tube portions 111 enter the plug housing 130, and simultaneously the smaller-diameter portions 135 of the ferrule assemblies 129 enter the transferring tube portions 111. And, the large-diameter portions 137 of the ferrule assemblies 129 abut against the ends of the transferring tube portions 111, while keeping suitable pressure therebetween by means of the springs 134.
With respect to the above conventional receptacle 102 of the optical connector 101, however, since the light receiving element module 106 and the luminescence element module 107 have to be inclined as shown with the arrow R in FIG. 18 when the modules 106, 107 are fitted into the receptacle 102, that is, the fitting work of the modules 106, 107 into the accommodating chambers 110 cannot be done smoothly.
And, the terminals 121,122 are likely to hit the terminal led-out portions 120 during the above fitting work and the terminals 121,122 would bend, which should disturb the assembly process thereafter.
Further, as is shown in FIGS. 17 to 20, since reversing work of the connector housing 104 would be required for easier fitting of the modules 106,107, the productivity of the receptacle 102 would not be good.
Here, the assembly process of the receptacle 102, in turn, is: the sleeve members 105 are fitted to the connector housing 104 in an arrow P direction after the longitudinal axis of the connector housing 104 is arranged vertically as shown in FIG. 17; the connector housing 104 is arranged horizontally by turning it in an arrow Q direction; the light receiving element module 106 and the luminescence element module 107 are accommodated in the connector housing 104 as shown in FIG. 19 by shifting them in an arrow R direction as shown in FIG. 18; the connector housing 104 is again arranged vertically by turning it in an arrow S direction; and the cap member 108 is fitted to the connector housing 104 in an arrow T direction.
The terminal led-out portions 120 have respective rear frames. And, the rear frames require such assembly process as the above, which hinders automatic assembly of the receptacle 102 and, therefore, improvement of the productivity of the receptacle 102 should be required.
In view of the foregoing, an object of the present invention is to provide a receptacle with high productivity.
In order to achieve the above-described object, as a first aspect of the present invention, a receptacle of an optical connector in accordance with the present invention includes: a connector housing having a front and rear openings; an optical element module having an optical element and to be accommodated in the connector housing; a sleeve member to be accommodated in the connector housing for relaying light; and a cap member to be fitted to the rear opening, wherein the connector housing is provided with a coupling portion including the front opening for coupling with a mating optical plug connected to an optical fiber cable having a ferrule member, an accommodating chamber to accommodate the optical element module and having a terminal led-out portion on a bottom wall of the connector housing for leading a terminal of the optical element module outward of the connector housing, and a transferring tube portion connecting the coupling portion with the accommodating chamber and being fitted with the ferrule member on a coupling portion side thereof and with the sleeve member on an accommodating chamber side thereof, while aligning the sleeve member with the optical element on a longitudinal axis of the transferring tube portion, and further wherein the rear opening and the terminal led-out portion are continuously formed.
As a second aspect of the present invention, in the structure with the above first aspect, an engaging portion is provided on side walls of the connector housing and a securing projection to engage the engaging portion is provided on the cap member for holding the cap member.
As a third aspect of the present invention, in the structure with either one of the above first and second aspects, the cap member is provided with a projecting portion projecting inward of the terminal led-out portion and toward the terminal.
As a fourth aspect of the present invention, in the structure with any one of the above first to third aspects, the cap member is provided with a pushing projection to push the optical element module toward the sleeve member.
According to the above-described structure of the present invention, the following advantages are provided.
(1) Since the optical element module can be fitted in the accommodating chamber without inclining it as the same way as the sleeve member and as the cap member in the same direction, and since the terminal led-out portion continues from the rear opening, the optical element module can be smoothly fitted in the accommodating chamber without any obstacle. Further, since assembly work, such as turning work of the connector housing in the assembly process, can be eliminated, automatic assembly work is easily available. Thereby, a receptacle with high productivity can be realized.
(2) Though the terminal led-out portion continues from the rear opening, the cap member is secured to the connector housing since the securing projection of the cap member engages the engaging portion of the connector housing.
(3) Since the cap member is provided with the projecting portion projecting inward of the terminal led-out portion, the optical element can fully perform.
(4) Since the cap member is provided with a pushing projection to push the optical element module toward the sleeve member, the optical element module can be put into close contact with the sleeve member.
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.